Antimony mercaptides have been proposed as stabilizers for vinyl halide resins to guard against degradation by heat during molding and working of the resin into useful articles. Prior art patents which disclose such antimony organic sulfur-containing compounds and their utility as stabilizers include U.S. Pat. Nos. 2,680,726; 2,684,956; 3,340,285; 3,399,220; 3,466,261 and 3,530,158. In past commercial practice, however, the antimony mercaptides have not been widely used as stabilizers because of various shortcomings including, for example, their propensity to exude from molded or worked PVC plastic stock, cost or lack of other advantages associated with their use which might outweigh such shortcomings. My U.S. Pat. No. 3,887,508 is directed to improvements in the utilization of antimony organic sulfur-containing compounds in combination with metal carboxylates. As described in my U.S. Pat. No. 3,887,508, the utility and efficiency of such antimony compounds are improved in the heat stabilization of vinyl halide resins to an unexpected degree. It has been observed, however, that such antimony compounds which are normally liquid tend to deteriorate or become unstable upon storage.